1. Field of Invention
The present invention relates to an assembly method for a device that employs electric ignition, such as an air bag device, and a method of distinguishing between two electroconductive pins provided in an electric igniter.
2. Description of Related Art
In an electric igniter having two electroconductive pins (a center pin and an eyelet pin) for electrifying a heating wire (a body that generates heat through electric resistance) or an igniter assembly using the electric igniter, positive and negative electrodes are usually connected to predetermined electroconductive pins, and when a positive or negative electrode is connected to the wrong electroconductive pin, a defective product is obtained.
FIG. 1 illustrates the structure of a known igniter assembly 10. An electric igniter 20 is coupled integrally to a metallic igniter collar 30 by a resin 31.
In the electric igniter 20, a center pin 21a is insulated from a metallic header (eyelet) 23 by a glass member 22 and connected to a heat-generating body (bridge wire) 24. An eyelet pin 21b is connected to the eyelet 23 and connected to the heat-generating body (bridge wire) 24 via the eyelet 23. An ignition agent 26 is charged into a tubular spacer 25 so as to press against the heat-generating body (bridge wire) 24. The eyelet 23 and the tubular spacer 25 are covered from the outside by a metallic cover 27, together forming an ignition portion of the electric igniter 20. Further, the metallic cover 27 of the ignition portion is covered by a resin cover 28 having an electric insulation property. A space 29 serves as a space for inserting a connector plug having a lead wire.
As shown in FIG. 1, the igniter assembly 10 has a structure in which a resin 31 is molded between the igniter 20 and igniter collar 30, and therefore it is impossible to distinguish between the center pin 21a and the eyelet pin 21b from the outer form thereof.
Conventionally, the center pin 21a is distinguished from the eyelet pin 21b by means of X-ray projection, but X-ray projectors and X-ray lamps are both expensive, leading to an increase in maintenance costs that is reflected in the manufacturing costs of the igniter JP-A No. 2001-165600 and JP-A No. 2006-35970 may be related arts of the present invention.